Derdriu

Old Irish

From derdrethar (“rages, resounds”), from dord (“to buzz, drone”).^[1]

Derdriu f (genitive Derdrenn)

a female given name, most famously borne by a tragic heroine of the Ulster Cycle.

Feminine n-stem
	Singular	Dual	Plural
Nominative	Derdriu	—	—
Vocative	Derdriu	—	—
Accusative	Derdrinn^N	—	—
Genitive	Derdrenn	—	—
Dative	Derdrinn^L, Derdriu^L	—	—
Initial mutations of a following adjective: ^H = triggers aspiration ^L = triggers lenition ^N = triggers nasalization

Old Irish mutation
Radical	Lenition	Nasalization
Deirdre	Deirdre pronounced with /ð(ʲ)-/	nDeirdre
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.

^ Stüber, K. (1998). The Historical Morphology of N-stems in Celtic. Ireland: Department of Old Irish, National University of Ireland, Maynooth, p. 103